Hypertension and Heart Failure Flashcards
Describe the different grades of hypertension
- Hypertension defined as 140/90 mmHg
- Grade 1: 140-159 / 90-99 mmHg
- Grade 2: 160-179 / 100-109 mmHg
- Grade 3: > 180 / >110 mmHg
List some non-pharmacological management of hypertension
- Patient education
- Maintain normal body weight and BMI
- Reduce salt intake to < 6g/day
- Limit alcohol consumption to < 3units/day for men and < 2 units/day for women
- Engage in regular aerobic physical exercise for > 30 minutes/day
- Consume > 5 portions of fresh fruit/vegetables daily
- Reduce intake of total and saturated fat
- Smoking cessation
List the main classes of antihypertensive drugs
- ACE inhibitors
- Angiotensin receptor blockers
- Calcium channel blockers
- Diuretics
- Alpha and beta blockers
- Direct renin inhibitor
- Centrally acting agents
Describe the mechanism of ACE inhibitors
- Eg. Ramipril, lisinopril
- Competitive inhibitor of angiotensin converting enzyme
- Reduction in formation of angiotensin II
- Arterial vasodilators
- Some venodilation
- Circulating aldosterone is reduced
- Potentiates the action of bradykinin (stops breakdown of bradykinin) - vasodilator
List the main ADRs of ACE inhibitors
- HARD
- Hyperkalaemia - reduced Na reabsorption leading to reduced K secretion
- Angio-oedema - increased circulating fluid
- Renal failure
- Dry cough due to bradykinin
Describe the mechanism of angiotensin receptor blockers
- Eg. Losartan, candesartan
- Bind to angiotensin AT1 receptor
- Inhibit vasoconstriction and aldosterone stimulation caused by angiotensin II
- Increased release of NO - vasodilator
- Inhibit vasoconstriction and aldosterone stimulation caused by angiotensin II
List the main side effects of angiotensin receptor blockers
- Renal failure
- Hyperkalaemia - reduced Na reabsorption leading to reduced K secretion
State the 3 classes of calcium channel blockers
- Dihydropyridines
- Phenylalkylamines
- Benzothiazepines
Describe the use of dihydropyridines
- Eg. Nifedipine, amlodipine
- Main calcium channel blocker used in hypertension
- Baroreflex mediated tachycardia
Describe the main side effects of dihydropyridines
- FOGS
- Flushing, sweating, throbbing headache
- Oedema - ankle swelling
- Gingival hyperplasia - increased size of gums
- Sympathetic nervous system activation - tachycardia and palpitations
Describe the uses of phenylalkylamines
- Eg. Verapamil
- Useful in treating angina and arrhythmia
- Depresses SA node and slows AV conduction
- Impedes calcium transport across the myocardial and vascular smooth muscle cell membrane
- Peripheral vasodilation and a reduction in cardiac preload and myocardial contractility
List the main side effects of phenylalkylamines
- Constipation
- Risk of bradycardia
- Reduce myocardial contractility (negative inotrope) - can worsen heart failure
Describe the uses of benzothiazepines
- Eg. Diltiazem
- Impedes calcium transport across the myocardial and vascular smooth muscle cell membrane
- Prolongs the action potential/effective refractory period - also useful in arrhythmias
- Peripheral vasodilation and a reduction in cardiac preload and myocardial contractility
- Not as effective as amlodipine in treating hypertension but less risk of heart failure - used in angina
- Less cardiac stimulation as side effect
List the main side effects of bezothiazepines
- Risk of bradycardia
- Congestion, cough
- Fever, runny nose
- Less negative inotropic effect than verapamil - can worsen heart failure
State the type of diuretics given as anti-hypertensives and its effect
- Mainly thiazides (bendroflumethiazide, indapamide)
- Reduces sodium reabsorption, thus reducing blood volume
- Also acts as vasodilator to lower total peripheral resistance
- Reduces sodium reabsorption, thus reducing blood volume
- Spironolactone given to secondary hypertension due to hyperaldosteronism
- Acts as angiotensin receptor blocker
Describe the effect of alpha blockers as antihypertensives and its ADRs
- Alpha blockers antagonize contractile effects of noradrenaline on vascular smooth muscle
- Reduce peripheral vascular resistance
- Eg. Doxazosin
- ADR - postural hypotension, headache and fatigue, oedema
Describe the effect of beta blockers as antihypertensives and its ADRs
- Beta blockers reduce heart rate and cardiac output
- Inhibit renin release
- Eg. Bisoprolol, atenolol
- ADR - lethargy, reduced exercise tolerance, bradycardia, cold hands, impaired tolerance
- Contraindication - asthma
Describe the action of direct renin inhibitor
- Eg. Aliskiren
- Binds to renin molecule and prevents cleavage of angiotensinogen to angiotensin I
Describe the action of centrally acting agents
- Reduce sympathetic outflow - work in the brain
- Eg. Methydopa (used in pregnancy), clonidine, moxonidine
- ADR - lethargy, depression
Describe the NICE guidelines on hypertension treatment
- Aged under 55 years give ACEi or ARB first line
- Aged over 55 or black person of african or caribbean origin give calcium channel blocker first line
- Have less effective RAAS - 2nd line would be to give ACEi/ARB or CCB if not given
- 3rd line is thiazide diuretic
- 4th line consider further diuretic or alpha/beta blocker
List common causes of heart failure
- Ischaemic heart disease
- Hypertension
- Cardiomyopathies - alcohol, idiopathic, chemotherapy, iron overload
- Valve disease
List non-pharmacological measures in treating heart failure
- Reduce salt intake
- Reduce blood pressure
- Reduce alcohol intake
Describe the first line treatment of heart failure
- ACE inhibitor / Angiotensin receptor blocker (ARB) - commonly given
- Vasodilation - reduce afterload to ease HF
- Improve ventricular remodeling
- ß-blocker - commonly given unless patient is asthmatic
- Reduce heart rate and blood pressure, which reduces work of heart
- Also reduces mobilisation of glycogen and negate unwanted effects of catecholamines
- Have to be careful and initiate at low dose as failing myocardium dependent on heart rate
List non-first line medication for heart failure
- Spironolactone - commonly given as HF treatment rather than as diuretic
- Loop diuretics
- Ivabradine - inhibition of funny channel reducing heart rate
- Sucubitril - increase ANP to increase natriuresis and diuresis
- Antiplatelet drugs
- Statin